Common Cooling System Leaks
11-17-2023, 03:07 PM
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Location: Colorado
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My Ride: E61
Model Year: 2008
Common Cooling System Leaks
I got a low coolant warning the other day as I was pulling out of my driveway. I immediately pulled back in and parked the car. I checked the coolant reservoir today hoping it was just the sensor, but the rod was definitely not where it should have been. I'll be getting the car up on stands for a number of repairs soon (finally), but until then where/are there any common places that develop leaks in the cooling system? The car is about to hit 100k, and I have no idea if the coolant reservoir has ever even been opened. It's not impossible the loss is just due to 100K miles of evaporation, but I figure that's probably pretty unlikely. I'll definitely be checking the plugs when I get it in the shop to see if any have been steam cleaned... Ditto the oil for any signs of milkshake.
11-20-2023, 09:41 AM
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The coolant reservoir is known to crack. Beyond that, just look at the radiator, the radiator hoses (particularly the ends) and the myriad of coolant / other hoses that carry antifreeze.
If you can't find it, add some UV dye to the coolant, and check it again next time it's low (with a UV light, of course).
If you can't find it, add some UV dye to the coolant, and check it again next time it's low (with a UV light, of course).
11-20-2023, 04:48 PM
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the coolant reservoir is known to crack. Beyond that, just look at the radiator, the radiator hoses (particularly the ends) and the myriad of coolant / other hoses that carry antifreeze.
If you can't find it, add some uv dye to the coolant, and check it again next time it's low (with a uv light, of course).
If you can't find it, add some uv dye to the coolant, and check it again next time it's low (with a uv light, of course).
11-22-2023, 12:51 PM
#5
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That would be the coolant tank or hose(s). The tank was tricky for me to inspect. I had to use a mechanics mirror and bounce a light off of it.
12-05-2023, 07:53 AM
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My Ride: 2008 550i 6-spd; 2007 530i Sport
Model Year: 2008
I just experienced this breakdown the past week on my 2008 550i. While pulling into my garage, I heard a slight pop; as I exited the vehicle I saw blue coolant running out under the car and into the driveway.
I immediately suspected a blown radiator hose but all the connections were good; so I moved on to all the other connecting lines with no success. So I started looking at the line underneath the expansion tank when I noticed a crack running down the entire side of the expansion tank.
I had purchased and replaced the tank in 2020 from FCP Euro so I ordered a new tank and I'll be returning the cracked one under their lifetime warranty.
I'm glad that it happened in my garage and not while cruising on a freeway risking a blown head gasket.
I immediately suspected a blown radiator hose but all the connections were good; so I moved on to all the other connecting lines with no success. So I started looking at the line underneath the expansion tank when I noticed a crack running down the entire side of the expansion tank.
I had purchased and replaced the tank in 2020 from FCP Euro so I ordered a new tank and I'll be returning the cracked one under their lifetime warranty.
I'm glad that it happened in my garage and not while cruising on a freeway risking a blown head gasket.
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